Frankpledge

A pledge or surety for the good behavior of freemen, -- each freeman who was a member of an ancient decennary, tithing, or friborg, in England, being a pledge for the good conduct of the others, for the preservation of the public peace; a free surety

. (b)

The tithing itself

.

Bouvier.

The servants of the crown were not, as now, bound in frankpledge for each other.
Macaulay.